Service jack



Jan. 6, 1959 H. soUTHl-:RWICK SERVICE JACK Fied Sept. l5. 1954 2Sheets-Sheet l 1N VEN TOR.

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IN1/EN TOR.

A rroR/VEYS- United States Patenti) SERVICE JACK Harold I. Southerwick,Whitefish Bay, Wis., assignor to Blackhawk Mfg. Co., West Allis, Wis., acorporation of Wisconsin Application September 15, 1954, Serial '.No.456,094

3 Claims. (Cl. 254-2) The present invention relates generally toimprovements in the art of lifting and lowering heavy loads, and relatesmore specifically to improvements in the construc- -tion .and operationof service jacks especially adapted to lift vehicles or parts thereof.

The primary object of my invention is to provide an improved jackassemblage for lifting and lowering relatively heavy articles such asvehicles, and which is simple but durable in construction and highlyeicient in operation.

In modern automobiles and light trucks the construction of the bodies issuch that it is extremely diicult to gain access to the Wheels .andunder carriages even with the aid of the ordinary swinging lever servicejacks. Perhaps the most convenient manner of gaining such free access isto lift the body of such a vehicle without necessarily elevating thechassis or frame, and while this may be accomplished with an ordinaryhigh lift bumper jack such procedure is extremely sl'ow, tedious .anddangerous. It has therefore been heretofore proposed to provide aso-called one-end bumper jack equipped with a special high lifthydraulic hoist cooperating with spaced saddles adapted to coact withvehicle bumpers at widely lseparated localities, but these prior devicesare relatively yobjectionable for various reasons.

The prior one-end bumper jacks besides being costly to construct due tothe use of special long stroke hydraulic hoists, are also relativelybulky and interfere with access to the trunk compartment when applied tothe rear bumper of an automobile. Then too, these prior jack assemblagesare rather difiicult to apply to diverse types of bumpers, `and tomanipulate so as to insure quick and safe action. The prior bumper jacksare moreover cumbersome to move, and embody parts which must be removedwhen not in use thus introducing danger of loss of such parts.

It is therefore an important object of the present invention to providean improved one-end bumper jack for automobiles and light trucks, whichobviates all of the objectionable features of the prior jacks of thistype, and which is compact and has dangerous movable parts wellconcealed so as to make it safely but effectively operable.

Another important object of this invention is to provide an improvedbumper lift which is exceptionally strong and powerful and dependable inoperation, as well as being rapidly applicable to various styles ofvehicle bumpers.

A further important object of the invention is to provide a speedy highlift jack assemblage which may be produced at low cost from standardstructural steel, and also embodies a standard compact hydraulic liftingand lowering unit having relatively short stroke.

Still another important object of my invention is to provide' a readilytransportable bumper jack for automobiles, which avoids obstruction totrunk, access when applied to lce the rear vehicle bumper, and all partsof which arepermanently attached to the unit when not in use.

An additional important object `of my present invention is to provide animproved safety rig for preventing accidental lowering of a jack whileloaded, and which automatically cooperates with the jack loweringmechanism when released.

Another important object of the present invention is to provide a wellproportioned and attractive service jack unit the functioning of whichcan be safely and plainly viewed by an operator so .as to insureaccurate performance, and which may be applied and manipulated by anovice. I f

These and other more specific objects and advantages of 'the inventionwill be apparent from the following detailed description from which itmay be noted that the gist of the improvement is the provision of aone-end vehicle bumper lift embodying a three wheel mounted portablechassis having upstanding parallel rigid guideways rigidly attached toan extensive base reaching forwardly of the guideways, a cantilever loadcarrier having one end guided by rollers and movable along the guidewayswhile its opposite free end extends forwardly over the chassis base andis provided with laterally spaced and adjustable bumper engagingsaddles, a hydraulic jack mounted upon the chassis and having a plungerl.and load carrier respectively, and a safety lever pivotally secured tothe chassis and being alternately cooperablewith the load carrier toprevent accidental' descent thereofV while loaded and with the reliefvalve of the jackto effect lowering -of the carrier. Y

IA clear conception of the several features constituting the presentimprovement and of the construction and operation of a typical one-endhydraulic bumper jack unit embodying the invention, may be had byreferring to the drawings accompanying and forming a part of thisspecification wherein like reference characters designate the same orysimilar parts in the various views.

Fig. 1 is a true photographic A.perspective view of a typical one-endhydraulic jack unit built in accordance with the invention and 'showingthe holding lever in active position; Y

Fig. 2 is a fragmentary somewhat enlarged and shortened rear perspectiveview of a similar jack assemblage,

showing the details of constructionV of the safety holding lever and itsconnections with load carrier .and with the lifting jack release valve;

Fig. 3 is a top view of the same one-end jack unit with the hydraulicjack omitted; and

Fig. 4 is a part sectional and fragmentary side elevation of theassemblage shown in Fig. 3, with portions broken away and omitted 'tomore clearly reveal internal structure of the portable unit.

While the invention has been shown and described herein as having beenembodied in a hydraulicjack unit especially adapted for use as a one-endor bumper service jack for automobiles, it is not the intent tounnecessarily restrict the use of the improved features to such portablechassis 6 having a pair of rigid parallel upstanding channels orguideways 7 mounted upon a sturdy base-8 which is provided at one endwith a-pair of coaxial wheels 9 and at its oppositeendwith -a transverseangle beam 10;a hydraulic jack 11 resting upon Patented Jain. 6,1959

the chassis base 8 and having a plunger member 12 movable between theguideways 7 and provided at its upper end with a roller 13; a cantileverload supporting elevator or carrier 14 guided by inner and outer rollers15, 16 respectively, for movement along the channel guideways 7 andbeing provided at its overhung end remote from these guideways with atransverse box beam 17 disposed above and parallel to the angle beam aexible element such as a chain 18 having one end secured to the chassis6 and its opposite end secured to the carrier 14 while its medialportion engages the plunger roller 13; an oscillatory pump operatinghandle 19 operatively connected to the liquid pump of the jack 11; and asafety lever 20 swingably suspended from the chassis base 8 and beingalternately cooperable with the load carrier 14'to positively preventlowering thereof, and with the release valve 21 of the jack 11 to efectlowering of the load carrier 14.

The chassis 6 may be sturdily fabricated from structural steel bars andplates welded or otherwise rigidly united, and the guideways 7 may beformed of standard channel stock while the reaction beam 10 may beformed of standard angle stock of suicient length to provide anextensive support for the unit. In order to facilitate transportation ofthe jack assemblage from place to place, a caster wheel 23 is providedat the medial portion of the reaction barl 10 and a transverse grip bar24 is also provided near the upper ends of the channel guides 7; and thecaster wheel 23 is adapted to be forced downwardly by a spring 25 whenthe jack is unloaded so as to lift the angle beam 10 away from theground, see Figs. 3 and 4. The caster wheel 23 thus cooperates with thetwo alined wheels 9 to provide a three point mobile support for theunloaded jack; and besides the grip bar 24, the upstanding guideways 7are also stiifened by a removable cap 26 and by a transverse fixed plate27 thus producing a rigid L-shaped chassis assembly.

The hydraulic jack 11 may be of any of the well known conventional typeshaving an oil supply reservoir, a reciprocable pump for transferring oilfrom the reservoir to the plunger displacement chamber to elevate theplunger, and a release or by-pass valve for returning the oil from theplunger displacement chamber to the supply reservoir. A typical jack ofthis type is shown in Brumder Patent No. 2,238,968, granted April 22,1941, and such a conventional jack 11 may be mounted centrally upon thechassis base 8 so that its plunger 12 and the roller 13 carried by theupper plunger end will reciprocate midway between the channel guideways7 and will probably cooperate with the medial portion of the flexiblechain element 18. The oscillatory handle 19 for actuating the pump ofthe hydraulic jack 11 is mounted upon a`pivot 29 journalled in the upperportion of one of the guideways 7 and the inner end of which has a crank30 secured thereto. The Swinging extremity of the crank 30 is connectedby a connecting rod with the piston of the jack pump which may be of anywell-known type such as shown in the above identified Brumder patent, sothat oscillation of the handle 19 will cause the jack plunger 12 torise.

The cantilever load supporting elevator or carrier 14 and its box beam17 may also be fabricated from structural steel, and the reactionrollers 15, 16 are journalled upon pins secured to the verticallywidened inner ends of the opposite side plates 32 of the carrier 14which are also rigidly united by means of a horizontal L-shaped bridgeplate 33, see Figs l to 4 inclusive. The mid-portion of this bridgeplate 33 has a cleat 34 mounted thereon for detachable attachment to oneend of the chain 18, and the opposite end of this chain is likewiseattachable to a similar cleat 35 secured to the mid-portion of thetransverse guideway reinforcing plate 27. The rollers 15, 16 are spacedapart vertically a considerable distance, and the upper axially alinedpair of rollers 15 coact with the inner surfaces of the adjacentparallel flanges of the channel guideways 7, `while the lower axiallyalined rollers 16 coact with the outer surfaces of these same flanges,thus providing an eifective anti-friction connection between thecantilever elevator`14 and the' chassis 6.

The transverse tubular box beam 17 which is rigidly attached to the freeends of the elevator side plates 32, is of considerable length havingsubstantially square transverse hollow cross-section and being providedat its opposite ends with torsion blocks 36 which absorb twistingstresses. Snugly slidably confined within the hollow beam 17 is a pairof overlapping supports 37 each carrying a saddle 38 at its outer end,and these saddles 38 are formed for disposition beneath and for liftingengagement with a load such as the bumpers or frames of automobiles andtrucks of various types. The saddles 38 may be adjusted to differentpositions relative to the adjacent ends` of the beam 17 in order toaccommodate bumpers of various lengths and to provide maximum stabilityfor the portion of the vehicle being lifted, and the elongated supports37 for the saddles 38 are relatively slidable to effect such adjustmentand are stopped by the blocks 36 and by a pin 36' coacting with lateralprojections 37.

The safety lever 20 is swingly supported at its lower extremity fromears 40 secured to the chassis base 8, and its upper extremity isprovided with a manipulating knob 41 while its medial portion has aseries of elevator holding teeth 42 formed thereon and with which alatch 43 formed integral with one of the side plates 32 of the carrier14 is coperable to positively prevent lowering of the elevator, as shownin Figs. 1, 2 and 4. The upper portion of the lever 20 extends through aslot 44 formed in the cap 26 and this lever is constantly urged to swingtoward the latch 43 by a spring 45 connecting its upper portion' withthe adjacent guideway 7. The medial portion of the holding lever 20 isadapted to engage an arm 46 secured to an upright pivot shaft 47 mountedon the chassis 6 when the lever is swung away from the latch 43, andthis pivot shaft 47 has another arm 48 near its lower end connected to alever 49 secured to the actuating stem of the release valve 21 by meansof a connecting rod 50 which is constantly urged in a clockwisedirection as viewed in Fig. 2, by a spring 51 so as to close the valve21 when the arm 46 is free.

When the improved bumper service jack unit has been constructed andassembled as above described, the elevator or load carrier 14 may bedropped into its extreme lowermost position when not in use, by merelyswinging the holding lever 20 away from the latch 43 on the carrier,whereupon the spring 25 associated with the caster wheel 23 will elevatethe chassis beam 10 away from the ground and will enable the entire unitto be transported from place to place upon the three wheels 9, 23. Thesaddles 38 may be readily adjusted so as to properly coact with thebumper of the vehicle to which the jack assemblage is to be applied, andafter these saddles 38 have been carefully positioned below the bumperwith the jack 11 preferably located approximately in the centralvertical longitudinal plane of the vehicle, the lever 20 should bereleased and the handle 19 may be oscillated to raise the plunger 12 andto thereby lift the load carrier 14 so as to cause the saddles 38 toelevate the vehicle body while simultaneously lowering the chassis beam10 into rm contact with the ground or oor against the action of thespring 2S.

During such lifting of the vehicle body, the rigid latch 43 formed onthe carrier 14 rides over the successive projections or teeth 42 on theholding lever and when sufficient lifting of the vehicle has beeneiected, and the handle 19 is released, the jack 11 will ordinarily holdthe elevator in fixed elevated position until the release valve 21 isoperated. However, if any leakage occurs in the jack, tending to causethe load to drop, then the latch 43 will drop into engagement with thenearest lower tooth 42 of the lever 20, and this lever will thereafterpositively maintain the vehicle elevated until the holding lever isreleased. It is to be noted that when the vehicle or load is beingelevated, the chain 1S rides over the plunger roller 13 and the reactionrollers 15, 16 ride along the opposite sides of the adjacent channelflanges with minimum friction loss; and when the load is being raisedand held in elevated position, the rollers 15, 16 effectively supportthe cantilever elevator at all times.

When the jack unit is thus applied to the bumper of an automobile ortruck, the body may be lifted high enough so as to permit free access tothe wheels and undercarriage; and if it is desired to lower the load, itis only necessary to swing the lever 20 out of engagement with the latch43 and against the arm 46 so as to rotate the pivot shaft 47 in aclockwise direction as viewed in Fig. 2. This rotation of the pivotshaft causes the arm 48 to swing the lever 49 through the connecting rod50 and against the action of the spring 51, sufficiently to open thejack release or by-pass valve 21, thereby permitting the liquid toescape from the plunger displacement chamber of the jack into the liquidsupply reservoir. As soon as the carrier 14 has been loweredsufficiently to entirely release the load, the spring 25 quickly becomeseffective to raise the chassis beam from the ground and to therebyrestore the caster wheel to active condition.

From the foregoing detailed description it will be apparent that thepresent invention in fact provides a portable service jack especiallyadapted to cooperate with the bumpers of a vehicle to lift the bodywithout necessarily elevating the vehicle chassis o r frame, and whichis simple, compact and durable in construction, as well as being rapidlyand safely transportable and manipulable. By utilizing a standardhydraulic jack 11 having its plunger 12 cooperable through a roller 13and a flexible element 18 with the load elevator 14, the cost ofproduction is reduced to a minimum and the resultant assemblage isrelatively low in overall height and does not interfere with access tothe vehicle trunk o-r hood when applied to the rear and front bumpersrespectively of an automobile. The improved safety lever 20 performs thedual function of holding the elevated load and of controlling thelowering of the hydraulic jack plunger 12; and the provision of themanipulating handle 19 which is permanently attached to the jack unitand therefore eliminates possible loss or misplacement of loose parts,also enables the operator to clearly observe the functioning of the jack11 and of the load carrier 14 without danger. The handle 24 alsofacilitates convenient transportation and positioning of the unit so asto cause the saddles 38 to most effectively engage the load, and sincethe more delicate and dangerous movable parts are housed between thesturdy channel beams 7 the mechanism is safely operable. The provisionof the torsion blocks 36 within the tubular beam 17 is also importantsince they eliminate possible twisting of this beam due to theoff-setting of the adjustable saddle supports 37, and the improved jackassemblage is applicable to loads other than automobile bodies andframes and has proven highly satisfactory and successful in actual use.

It should be understood that it is not desired to limit this inventionto the exact details of construction and operation of the service jackspecifically shown and described herein, since various modificationswithin the scope of the appended claims may occur to persons skilled inthe art.

I claim:

1. A portable jack assemblage comprising, a transportable chassis havingthereon upstanding parallel guideways, an hydraulic lift mounted uponsaid chassis and having a load lifting plunger movable upwardly betweensaid guideways and also having a pump for raising and a release valvefor effecting lowering of the plunger, a load carrier guided formovement along said guideways,

a flexible element having one end secured to said chassis and itsopposite end secured to said carrier while its medial portion is movablycooperable with the upper end of said plunger to vary the elevation ofthe carrier relative to the chassis, a pump operating handle mountedupon one of said guideways and being operatively connected with saidpump to effect raising of said plunger and said carrier, and a loadholding lever mounted upon said chassis and being directly cooperablewith said carrier to sustain the load, said lever being swingableindependently of said pump operating handle to release the load andbeing formed for cooperation with said release valve to effect loweringof said plunger and carrier when the lever is swung into load releasingposition.

2. A portable jack assemblage comprising, a transportable chassis havingthereon upstanding parallel guideways, an hydraulic lift mounted uponsaid chassis and having a load lifting plunger movable upwardly betweensaid guideways and also having a pump for raising and a release valvefor effecting lowering of the plunger, a load carrier guided formovement along said guideways and having thereon a latch, a flexibleelement having one end secured to said chassis and its opposite endsecured to said carrier while its medial portion is movably cooperablewith the upper end of said plunger to vary the elevation of the carrierrelative to the chassis, a pump operating handle fulcrumed upon one ofsaid guideways and being operatively connected with said pump to effectraising of said plunger and carrier, and a load holding lever fulcrumedupon said chassis and having thereon a series of teeth cooperable withsaid carrier latch to positively sustain the load in various elevatedpositions when the lifting force acting upon said plunger fails, saidlever being swingable to release the load and being formed forcooperation with said release valve to effect lowering of said plungerand carrier when the lever is swung into load releasing position.

3. A portable jack assemblage comprising, a transportable chassis havingthereon upstanding parallel guideways, an hydraulic lift mounted uponsaid chassis and having a load lifting plunger movable upwardly betweensaid guideways and also having a pump for raising and a release valvefor effecting lowering of the plunger, a load carrier guided formovement along said guideways and having thereon a latch, a eXibleelement having one end secured to said'chassis and its opposite endsecured to said carrier while its medial portion is movably cooperablewith the upper end of said plunger to vary the elevation of the carrierrelative to the chassis, a pump operating handle fulcrumed upon one ofsaid guideways and being operatively connected with said pump to effectraising of said plunger and carrier, a load holding lever fulcrumed uponsaid chassis and being manipulable independently of said pump operatinghandle, said lever having thereon a series of teeth cooperable with saidvcarrier latch to positively sustain the load in various elevatedpositions when the lifting force acting upon said plunger fails andbeing formed for cooperation with said release valve to effect loweringof said plunger and carrier when the lever teeth are detached from saidlatch, and means for constantly resiliently urging said teeth towardsaid latch.

References Cited in the file of this patent UNITED STATES PATENTS2,216,058 Thompson Sept. 24, 1940 2,320,600 Howell June 1, 19432,664,073 Pine Dec. 29, 1953 2,669,422 Branick Feb. 16, 1954 2,709,015Sasgen et al. May 24, 1955 2,736,531 Wilson Feb. 28, 1956 2,763,465 Tosiet al. Sept. 18, 1956 FOREIGN PATENTS 582,188 Great Britain Nov. 7, 1946

